Lake Warnock
Atchison County, Kansas38 acresView mapDirections
KDHE publishes the water-quality measurements for Lake Warnock. Here is what has been measured.
- Hypereutrophic
- Impaired · Metals (other than mercury)
- Limited data
Lake Warnock in Atchison County, Kansas has water-quality measurements published by KDHE, shown here as reported. Water clarity: 1.7 ft visibility. Phosphorus: 509.5 µg/L. Chlorophyll-a (algae): 219 µg/L. Surface area: 38 acres.
Lake Warnock is a 38-acre highly nutrient-loaded hypereutrophic lake in Atchison County, Kansas. Overall water quality is improving over recent sampling years. Compared to the 1 other monitored lakes in Atchison County, Lake Warnock ranks #2 for water quality.
Source: EPA Water Quality Portal sampling records, KDHE, last sampled 2017-06-12. Methodology: how these readings are compared.
Lake Warnock covers about 38 acres in Atchison County. For a place on the water, look through cabin and lake-house rentals near Lake Warnock on Vrbo. For a hotel or motel room, Booking.com and Expedia both search around the lake.
Swimming conditions
Readings onlyRecreation use not supported
Based on clarity and algae readings from past sampling — there is no live water temperature and a current cyanobacteria reading for this lake. Check your state or county health department before you swim.
Nutrient and algae readings are not a swimming clearance. Lake Warnock is listed impaired under Clean Water Act §303(d) (IR 5) for metals (other than mercury), nutrients (phosphorus, nitrogen), pesticides, pH / acidity. Check local advisories before you swim.
Whether Lake Warnock is safe to swim in today is a call for the Kansas Department of Health and Environment and the county health department, who post current advisories. LakeQuality does not issue swimming clearances.
Water quality measurements for Lake Warnock
These are the measurements KDHE publishes for Lake Warnock, shown as reported. The condition class beside each reading is the EPA National Lakes Assessment class for this lake’s ecoregion.
Very murky, less than 1.7 ft of visibility. Phosphorus 509.5 µg/L. Chlorophyll-a 219 µg/L. TSI 82.
| Measure | Reading | Where it sits |
|---|---|---|
| Water clarity (Secchi depth) | 1.7ft | Measured, not scored How deep a black-and-white disk stays visible from the surface. Higher is clearer. |
| Total phosphorus | 510µg/L | Poor GoodFairPoor |
| Chlorophyll-a (algae) | 219µg/L | Poor GoodFairPoor |
| Trophic state (TSI)Carlson's 0–100 index of how much algae a lake can support, from clarity, phosphorus and chlorophyll-a. | 82 | Hypereutrophic OligotrophicMesotrophicEutrophicHypereutrophic |
Very high nutrients, dense algae, poor clarity
Ask about Lake Warnock
Answers come straight from the public measurements and survey records on this page.
Lake Details
Surface area
38 acres
No bathymetric survey has been published for Lake Warnock, so its depth is not documented here.
Stays via Stay22
Stays near Lake Warnock
Compare lakeside cabins, hotels, and vacation rentals near Lake Warnock in Atchison County, Kansas — live availability and prices for your trip. Switch the map to Satellite to see the lake and how close each stay is to the water. The water-quality readings cover nutrients and algae, not lodging. Cabins and rentals around Lake Warnock are listed below.
Top-rated places to stay near Lake Warnock
Prices for Oct 30–Nov 1, 4 adults. Change dates on the map below.
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Fishing Lake Warnock
Water quality readings over time
2 seasons of samples on record (2013–2017). Calling a direction takes at least 4 years of the same measurement.
Water clarity
Improving2 years
Phosphorus
Improving-109.37 µg/L/yr2 years
Chlorophyll-a
Improving-108.25 µg/L/yr2 years
Reservoir Info (USACE NID)
Lake Warnock is a man-made reservoir impounded by the Frd No 23 (completed 1962), built primarily for flood risk reduction on the Brewery Creek; earth-type dam, 52 ft tall and 1,313 ft long.
- Surface area
- 38 ac
- Normal storage
- 24 ac-ft
- Max storage
- 2,660 ac-ft
- Drainage area
- 2.84 sq mi
- Hazard class
- High
- Owner
- ATCHISON, CITY OF
All listed purposes: Flood Risk Reduction;Fire Protection, Stock, Or Small Fish Pond;Recreation.
Source: USACE National Inventory of Dams, NID ID KS02010 · Operator website · Matched by proximity (0.09 km)
EPA Impairment Status
Lake Warnock is officially listed as impaired under Clean Water Act §303(d) in the 2024 EPA reporting cycle (IR category 5).
Causes of impairment
Designated uses not supporting: Drinking water, Aquatic life, Recreation.
Source: EPA ATTAINS assessment unit KS-LM039801 · Official waterbody report
Nearby Lakes in Atchison County
Frequently asked questions about Lake Warnock
Where is Lake Warnock?
- Lake Warnock is a lake in Atchison County, Kansas. Its water-quality measurements are published by KDHE and shown on this page as reported.
What is the water quality of Lake Warnock?
- Lake Warnock in Atchison County, Kansas has water-quality measurements published by KDHE, shown here as reported. Water clarity: 1.7 ft visibility. Phosphorus: 509.5 µg/L. Chlorophyll-a (algae): 219 µg/L. Surface area: 38 acres.
Is Lake Warnock safe to swim in?
- Nutrient and algae readings are not a swimming clearance. Lake Warnock is listed impaired under Clean Water Act §303(d) (IR 5) for metals (other than mercury), nutrients (phosphorus, nitrogen), pesticides, pH / acidity. Check local advisories before you swim.
Explore Lake Warnock across LakeQuality
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Where this data comes from
10 measurements from 1 monitoring station, 2013–2017. Retrieved from the EPA Water Quality Portal on 2026-08-02.
Collected and reported by
- Kansas Department Of Health And Environment
21KAN001_WQX10 samples · 2013–2017
Analytical methods
- Depth, Secchi disk depth
- Phosphorus by Colorimetry
- 10200 H ~ Chlorophyll a-b-c Determination
Monitoring station identifiers (1)
EPA condition classes from the National Lakes Assessment (EPA 841-R-24-006, Table 6-3), applied by ecoregion. See where the data comes from and data sources.
Other records on this page
Impairment status from EPA ATTAINS 303(d) database